1. Field of the Invention
The present invention relates generally to chucks and, more particularly, is concerned with a workpiece holding assembly for use on the chuck.
2. Description of the Prior Art
Rotary machining apparatuses, such as lathes and grinding machines, are customarily equipped with chucks to grip and center a workpiece. Typically, a chuck has jaws movably mounted on guideways extending in radial relation to a central rotational axis of the apparatus. The jaws are opened or closed relative to the workpiece upon being radially moved simultaneously along the guideways by turning a pinion to cause rotation of a helical track or scroll engaged with the jaws. Representative of the prior art are the chucks disclosed in U.S. Pat. Nos. to Kuchenbrod (2,708,118), Strauss (2,896,958), McMullen (3,945,654), and Rohm (4,270,763 and 4,362,306); in a British patent to Friedmann (No. 148,383): in a Japanese patent to Kitagawa (58-211807): in a Russian inventor's certificate to Azerb Poly (No. 910,370); and in catalog 84 of the Buck Chuck Company of Kalamazoo, Mich.
One approach to increasing the versatility and usefulness of a given chuck is exemplified by the Kuchenbrod patent. In this patent, adjustable jaw assemblies are provided for attachment to the master jaws of the chuck. The jaw assemblies can be adjusted to grip odd or irregular workpieces and are capable of holding them more securely than are the master jaws of the chuck.
The basic approach of the Kuchenbrod patent appears to offer promise as a way to increase the versatility and usefulness of a chuck. However, the particular jaw assemblies proposed in this patent are believed to have several drawbacks. They are composed of too many parts, their design seems unduly complex, and their fabrication would probably be too costly for them to be practical.
Consequently, a need exists for improvement of the approach taken in the Kuchenbrod patent to increase the versatility and usefulness of a workpiece holding and centering chuck.